Monthly Archives: August 2017

Unhappy with your render finish?

It is always disappointing if you’ve paid for a job and you’re not happy with the result. We get a quite a few queries from people who have had their properties rendered and are sadly not happy with the finish. There are several common issues that tend to arise:

• The render has lots of hairline cracks over it (or even large cracks!)
• The render finish is not consistent across the wall surface
• The render is the wrong colour
• Algae seems to be growing on the newly-rendered wall
• The render seems to be bubbling

Having spent lots of money on giving your home a face lift, it can be pretty gutting if the end result does not live up to expectations. The good news is that at EWI Store we have all the products you will need to help you fix the issue, so you can once again be proud of your home!

Our most popular products are all thin coat render systems. These consist of a 6mm base coat layer with an embedded fibreglass mesh topped with a render textured finish. The beauty of these renders is the fact they are so flexible, meaning they don’t crack!

Unhappy with your pebbledash finish? Check out our blog on replacing pebbledash with coloured render.

Cracks forming in your render?

We get lots of people who want to fix cracked render and they ask whether it is enough just to go over their cracked render with our textured render topcoat. The answer here is, sadly, no! The textured render topcoat gets applied extremely thinly – take for example our popular 1.5mm Silicone Silicate render system – this is applied on top of the base coat at a thickness of just 1.5mm. The render can’t be applied directly on top of previous render for two reasons – firstly the surface on which our thin coat renders are applied need to be perfectly flat. If it isn’t flat, it is impossible to achieve the required textured finish – the base coat provides this perfectly flat surface on which the top coat sits. The second reason is that even if the wall was incredibly flat, were you to apply the render topcoat only (i.e. without the base coat layer), it would not have sufficient strength and so would fail in a short period of time.

When applying our render systems on top of another render finish, we would always recommend using EWI-225 Premium Adhesive. This is stronger than the EWI-220, and therefore the whole system will be that little more robust. This is pretty important as, if you’re already replacing one render system with another, the last thing you want to have to do is to replace it again 5 years down the line. Our render-only systems should be crack-free for a minimum of 10 years if installed correctly.

So if you have render that has been newly installed and you are already seeing cracks, use our EWI-225 Premium Adhesive plus EWI-66640 Fibreglass Mesh for the base coat, and then apply our top coat renders (ideally Silicone or Mineral).

The same applies if the render finish is not consistent across the wall surface. To be honest, this often occurs because the installers lack the skill to do the job. If you have had your property rendered and you are not happy with the finish, give us a call – we have a network of approved renderers and external wall insulation installers who will all do a great job! The answer to solving the issue is the same though – a new layer of basecoat, (with embedded fibreglass mesh) and then the render top coat to give the textured finish.

Unhappy with the colour of your render?

If you simply want to change the colour of your home, then the solution is quite a bit cheaper! You just need a bucket of our Silicone Paint. The Silicone Paint is breathable and can be coloured to meet your design requirements. It can be painted on most renders and two coats should do the job, regardless of the colour of the original render (check out ‘The Best Masonry Paint? Silicone Paint’). In some cases you will need to prime the existing render before applying our Silicone Paint – the easiest thing to do if you are unsure is give us a call, and one of our team will be happy to help!

Got algae growing on your render?

Unfortunately, algae growth can occur very quickly on new render. There are some renders that are particularly liable to algae growth, and one of these is Acrylic render – many people look to acrylic render since it is the cheapest option to buy and therefore it keeps install costs down. On the other hand, silicone/mineral renders will tend to inhibit algae growth, but be mindful of where you house is situated. If you live in middle of woods, then unfortunately the chances of having no algae growth at all is unlikely, even if you use silicone render. Here you may wish to pick a slightly darker colour so that light algae growth won’t show. If Acrylic render has been installed though, you can apply a new layer of base coat and silicone render and this will certainly help.

If you’re unhappy with a past render job done on your property,just get in touch and we can give you some suggestions of how to improve it!

Using EWI Pro renders on Render Carrier Board

Render carrier boards provide a solid base on which our render systems can be installed. There are lots of different types of render board available here in the UK, and the good news is that our EWI Pro renders and adhesives can be used on pretty much all of them! Render carrier boards are often used when constructing timber frame or steel frame buildings. Our renders are suitable for use on boards including Bluclad, Renderflex and Rendaboard, but for a list of approved boards, see our ultimate guide to render carrier boards.

Why use render carrier board?

The render carrier board provides a stable base on which the new render top coat can be applied. The carrier boards are characterised by high tensile strength which resists bending to prevent cracking and deformity, but they also tend to be breathable, moisture resistant and non-combustible. In many cases too, the render boards can take a considerable amount of impact force before cracking ensuring that your home will stand up to the elements!

Render carrier boards often are manufactured in two thicknesses 9mm and 12mm; however we recommend using 12mm render boards where available (Blueclad, for example, only do a 10mm board). The extra thickness of the carrier board just gives it that bit more strength – so it’s always worth using if you get the option.

Joining neighbouring render carrier boards

The render carrier boards tend to be attached to either wooden battens or a steel frame and are staggered. It is good practice that the carrier boards should also have a 3 – 5mm gap between them and their neighbouring board. We suggest using a 5mm window packer as a gauge to get it looking neat and tidy!

Once the boards are attached to the timber/steel battens, it is time to mesh the joints. The easiest way to do this is to cut 200mm strips of our EWI-66640 Fibreglass Mesh and use an approved fibreglass mesh tape to hold these in place. After this, it is then time to apply the basecoat to the render carrier boards.

EWI-225 Premium Adhesive is perfect for render carrier boards!

Our EWI-225 Premium Adhesive is the preferred product for basecoating the render carrier boards. The reason for using the EWI-225 is that the carrier boards don’t require priming before applying it. The EWI-225 is incredibly strong and has unsurpassed adhesion to the carrier boards, so once you put it on the boards you can be sure it won’t go anywhere. If you are one of our approved installers, we will provide 10 year warranties on our EWI-225 Render-only system – a nice selling point for customers.

Apply the EWI-225 to the render carrier boards using a notched trowel. This is the easiest way to ensure you apply the same thickness of adhesive across the boards. A 10mm notched trowel held at 45 degrees to the render carrier board will give you the required 6mm depth of adhesive.

Embedding the Fibreglass Mesh in render carrier board systems

Once the adhesive has been applied, it is time to sink the EWI-66640 Fibreglass mesh into it. The mesh is embedded in the adhesive from top to bottom rather than horizontally from side to side. You will notice on the rolls of EWI-66640 Fibreglass Mesh there are markers at each end – these signify the 100mm overlap required when embedding the layers of mesh. They should always overlap the previous piece of mesh embedded by 100mm.

To embed the mesh, turn the notched trowel over so you have the straight edge of the trowel and draw it up from the bottom of the mesh you are looking to embed. By drawing the trowel up and pressing down on the mesh, adhesive will be pulled through the mesh and it should disappear. Once completed, there should be no visible signs of the fibreglass mesh anywhere – it needs to be completely embedded before applying the top coat primer.

Once the EWI-225 Adhesive has gone off, it is time to prime the wall, prior to applying the final top coat of render. The product that is used to prime the wall is our EWI-333 Silicone Primer which can be painted on or applied using a roller. If you are using a very vibrant colour, then we suggest tinting the primer too – otherwise the white primer may show through the final top coat render (hopefully it won’t, but the top coat is very thin so there is a small risk this can happen).

Applying render to render carrier boards

So, having left the primer to go off, you are now ready to apply the top coat render. This is the decorative layer that ensures the render system is weatherproof. Our silicone renders (EWI-075 Silicone Render or EWI-040 Silicone Silicate Render) are through-colour renders, meaning they are coloured straight out the bucket (you don’t need to paint them after). The silicone renders are also breathable and hydrophobic, so they self-clean. Once the render has been applied to the wall surface, you then need to rub the render using a plastic render float to give the required texture to the render. The result is a maintenance-free, aesthetically pleasing finish!

It is also worth mentioning that we do all our colour tinting here in the UK, meaning we can get you coloured render the very next day!

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